A switch including multiple switching devices may be provided in a data communication network to enable data communication between multiple network stations connected to various ports of the switch. A logical connection may be created between receive ports and transmit ports of the switching devices to forward received frames to appropriate destinations. Based on frame headers including source and destination address information, a frame forwarding arrangement makes a frame forwarding decision about which, if any, ports the frames will be forwarded to.
To support frame forwarding operations, each switching device maintains an address table containing source and destination address information. Whenever, a switching device receives a frame, it reads the source address of the frame, and if this address is not found in the table, an address entry corresponding to the port from whence the frame came may be added to the table. The switching device also reads the destination address of the frame, and if this address can be matched to a particular port, the device will forward the frame to that port.
In a switching system using multiple switching devices, the destination address of a frame may be not found in the address table of a particular switching device that receives the frame. In this case, the device will “flood” the frame to all of its ports and to an expansion bus connecting various switching devices of the switching system. However, frame flooding is undesirable because it uses up the bandwidth of the system.
Therefore, it would be desirable to create a mechanism that enables a switching system to share address table information among switching devices.